Dwdm
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This document discusses dense wavelength division multiplexing (DWDM) technology. It begins with an overview of DWDM, describing how it multiplexes multiple optical carrier signals onto a single optical fiber using different laser light wavelengths. It then provides details on DWDM network architecture, including optical transponders, multiplexers/demultiplexers, optical add-drop multiplexers, optical fiber amplifiers, and the optical supervisory channel. The document also discusses optical frequency bands defined by the ITU and advantages and limitations of DWDM networks.
Dwdm
- 1. MADE BY :- SHUCHISHMAN BURMAN 090103508 ECE-D
- 2. Introduction Multiplexing a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium Types Time division multiplexing Frequency division multiplexing Optically Time division multiplexing Wavelength division multiplexing
- 3. •WDM is a technology which multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths of laser light to carry different signals. • There are two types of WDM— > Coarse WDM > Dense WDM
- 4. Evolution of DWDM Late 1990’s 1996 DWDM Early 1990’s Narrowband WDM 1980’s Wideband WDM 16+ channels 100~200 GHz spacing 2~8 channels 200~400 GHz spacing 2 channels 1310nm, 1550nm 64+ channels 25~50 GHz spacing
- 5. Dense wavelength division multiplexing (DWDM) is a fibre-optic transmission technique that employs light wavelengths to transmit data parallel-by-bit or serial- by-character. dense wavelength division multiplexing (dwdm)
- 8. The following steps describe the system :- 1. The transponder accepts input in the form of standard single mode laser. The input can come from different physical media and different protocols and traffics types. 2. The wavelength of each input signal is mapped to a DWDM wave length. 3. DWDM wave length from the transponders are multiplexed into single optical signal and launched into fiber 4. A post amplifier boosts the strength of the optical signal as it leaves the system 5. Optical amplifier are used along the fiber span as needed 6. A pre amplifier boosts the signal before it enter the end system 7. The incoming signal is de multiplexed and fed to respective receiver 8. From receiver they are transmitted to different system according to requirement
- 9. OVERVIEW OF DWDM NETWORK ARCHITECTURE Optical Transponder Unit (OTU): The major function of the OTU board is to employ the Optical /electrical/ optical conversion made to realize wave length conversion. OTU includes transmission OTU and receiver OTU.
- 10. Optical Multiplexers and De-multiplexers Unit (OMU & ODU):- As DWDM system send signal from several source over a single fiber, they must include some means to combine the incoming signal. This is done with multiplexers, which take optical wavelength from multiple fiber and converge them into one beam Multiplexing & Demultiplexing using Prism and Lens De multiplexing Using Array of Wave Guide Optical Add Drop Multiplexers (OADM): This is the area in which multiple wave length exist .It is often desirable to be able to remove or insert one or more wavelength at some point along this spans. An OADM performs this function. Rather than combining and separating all wave length, the OADM can remove some while passing others.
- 11. Optical Fiber Amplifier (OBA, OLA, OPA): Optical amplifiers also can be used to boost signal power after multiplexing or before de multiplexing By making it possible to carry large loads that DWDM is capable of transmitting over long distance, the EDFA (Erbium Doped Fiber Amplifier) was key enabling technology Optical Supervisory Channel (OSC): It is used for supervision of DWDM networks and its components. It works on wave length of 1510 nm and speed of 2.048 Mb/s .It is use in Network Monitoring System.
- 12. 2-May-15 12 OPTICAL BANDS EXTENSIVE USE OF WAVELENGTHS DIFFERENT VENDORS:INTEROPERABILITY ISSUES NEED FOR STANDARD WAVELENGTH VALUES ITU Classification of bands Standard values : ITU Grid Center frequency: 193.10THz (1552.52 nm) Standard spacing of 200, 100, 50 GHz for different applications
- 13. 2-May-15 ALTTC/TX-I/DWDM 13 ITU-T BAND ALLOCATION Optical Supervisory channel 1500 1520 1530 1542 1547 1560 1620 RED BAND C BAND L BAND BLUE BAND • C BAND PRODUCTS ARE COMMERCIALLY AVAILABLE. • ERBIUM DOPED FIBRE AMPLIFIERS SUITABLE FOR ‘C’ BAND. • GAIN IN RED BAND FLATTEST FOR EDFA. • SOME MANUFACTURERS PROVIDE 16 CHANNELS IN RED BAND ONLY. OTHERS USE BOTH RED & BLUE BANDS.
- 14. • Capacity increase : Large aggregate transmission capacity. • Upgradability : Customer growth without requiring additional fiber to be laid. • Flexibility : Optical Add/Drop Multiplexing (OADM) Optical Cross connect (OXC) • Scalability : The possibility to add new nodes to the network. • Network Transparency : Independence of data rate, format & protocols.
- 16. 2-May-15 ALTTC/TX-I/DWDM 16 LIMITATIONS • DWDM TRANSMISSION IS ANALOG. THE IN LINE AMPLIFIERS ARE ALSO ANALOG. THIS IMPLIES THAT THE SIGNAL TO NOISE RATIO WORSENS WITH DISTANCE. • FIBRE DISPERSION IS ANOTHER LIMITATION.